1. Field of the Invention
The present invention relates auto focusing such as for an imaging apparatus.
2. Description of the Related Art
Recently, as multimedia apparatuses and Internet connectivity have become increasingly widespread, it has become easier for users to store photographs they have taken on multimedia apparatuses or to upload the photographs to Internet blogs. Consequently, camera ownership has risen in recent years.
Modern cameras support an automatic focusing (AF) function, which enables automatic focus adjustment. In general, AF systems use a contrast method or phase difference detection method.
The phase different detection method can focus in a short time. However, a dedicated detection apparatus is required with a separate optic system that guides light for focus detection. The phase difference detection method is generally used in a digital single-lens reflex (DSLR) camera.
Since the contrast method does not require a separate space, it is mainly used in a small-sized compact camera. However, since the contrast method cannot directly measure an amount of defocus, the measurement should be repeated several times.